Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Major Neurocognitive Disorder

Related Terms

Alzheimer's-type Dementia (DSM-IV-TR)

Chronic Organic Brain Syndrome (DSM-IV-TR)

Frontotemporal Neurocognitive Disorder (DSM-5)

Mild Neurocognitive Disorder (DSM-5)

Multiple Cognitive Deficits (DSM-IV-TR)

Neurocognitive Disorder due to Alzheimer's Disease (DSM-5)

Neurocognitive Disorder due to Another Medical Condition (DSM-5)

Neurocognitive Disorder due to HIV Infection (DSM-5)

Neurocognitive Disorder due to Huntington's Disease (DSM-5)

Neurocognitive Disorder due to Multiple Etiologies (DSM-5)

Neurocognitive Disorder due to Parkinson's Disease (DSM-5)

Neurocognitive Disorder due to Prion Disease (DSM-5)

Neurocognitive Disorder due to Traumatic Brain Injury (DSM-5)

Neurocognitive Disorder with Lewy Bodies (DSM-5)

Senile Dementia (DSM-IV-TR)

Senile Dementia of the Alzheimer Type (DSM-IV-TR)

Substance/Medication-Induced Neurocognitive Disorder (DSM-5)

Unspecified Neurocognitive Disorder (DSM-5)

Vascular Dementia (DSM-IV-TR)

Vascular Neurocognitive Disorder (DSM-5)

Differential Diagnosis

Alcohol/substance abuse

Amnestic disorders

Delirium

Depressive disorder (pseudodementia)

Focal brain syndromes

Malingering

Normal aging

Specialists

Clinical Psychologist

Internal Medicine Physician

Neurologist

Occupational Therapist

Physical Therapist

Psychiatrist

Comorbid Conditions

Alcohol or substance abuse disorders

Depressive disorders

Infection

Other psychiatric disorders

Vascular disease

Factors Influencing Duration

Diagnosis and treatment of a treatable dementia may lead to restored mental function. The severity of dementia and extent of available social supports can influence disability. Most forms of dementia are incompatible with gainful employment.

Overview

Dementia is a general term describing a group of disorders in which memory and thought processes (cognition) become impaired for a period of at least 6 months. Unlike mental retardation, dementia involves a decremental change in thinking abilities relative to baseline.

In many forms of dementia, such as Alzheimer's disease, Lewy body disease, and other neurodegenerative disorders, symptoms develop slowly, are relatively stable rather than fluctuating, and continue into a slow worsening. However, other forms of dementia, such as vascular dementia associated with small strokes (multi-infarct dementia) may begin abruptly and worsen in stepwise fashion, with relative stability between each decline. In dementia secondary to head trauma or encephalitis, memory problems are worst at the outset, and remain relatively stable or may even improve with time.

Impaired memory is a prominent and early symptom of dementia. New skills and knowledge are difficult to learn, while old skills and knowledge are eventually lost. Valuables may be lost, such as a wallet or keys. The person may become lost, even in familiar surroundings. Late in dementia, individuals may forget their occupation, family members, or even their name. Other symptoms are difficulty naming objects or people (anomia), rambling speech, difficulty performing certain activities (apraxia), or failure to recognize certain objects (agnosia). Executive functions, such as thinking abstractly, planning, and initiating complex activities, can be impaired. Poor judgment and insight are common. The individual usually has little or no awareness of memory loss or other abnormalities. Individuals have an unrealistic view of their capabilities or their future. For example, they may talk of starting a business or driving. There can be mood and sleep disturbances. False beliefs (delusions) are common, especially paranoid delusions involving others stealing from them or conspiring against them. Individuals with dementia may have further deterioration of cognitive abilities with stress, either physical stress such as a viral illness or minor surgery, or psychological stress such as bereavement.

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the neurocognitive disorders (included in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision [DSM-IV-TR] in the section Dementia, Delirium, Amnestic, and Other Cognitive Disorders) begin with delirium, followed by the syndromes of major neurocognitive disorder, mild neurocognitive disorder, and their etiological subtypes (see Related Terms). The neurocognitive disorder category encompasses the disorders in which the primary clinical deficit is in cognitive function, and that are acquired rather than developmental. Cognitive deficits are present in many if not all mental disorders (schizophrenia, bipolar disorders); however, the neurocognitive disorder category includes only disorders whose core features are cognitive. In neurocognitive disorders, impaired cognition represents a decline from a previously attained level of functioning, and has not been present since birth or very early life.

The fact that the neurocognitive disorders are syndromes for which the underlying pathology, and frequently the etiology, can potentially be determined, makes them unique among DSM-5 categories. Dementia is subsumed under the newly named entity major neurocognitive disorder (although the term dementia is retained in DSM-5 for continuity, and is not precluded from use in the etiological subtypes in which that term is standard). DSM-5 recognizes a less severe level of cognitive impairment, mild neurocognitive disorder (included in the DSM-IV-TR under cognitive disorder not otherwise specified). Several of the neurocognitive disorders frequently coexist with one another.

Although dementia is the customary term for disorders like the degenerative dementias that usually affect older individuals, the term neurocognitive disorder is widely used and frequently preferred for conditions affecting younger individuals, such as impairment due to traumatic brain injury or HIV infection. The major neurocognitive disorder definition is somewhat broader than the term dementia, in that individuals with substantial decline in a single domain can receive this diagnosis, most notably the DSM-IV category of amnestic disorder, which would currently be diagnosed as major neurocognitive disorder due to another medical condition and for which the term dementia would not be used.

Incidence and Prevalence: Prevalence ranges from about 1.5% for individuals age 65 to 69, up to 16% to 25% for those over 85 (DSM-IV-TR) (or 30% to 50% ("Dementia")).

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